Electromagnetic circuit breakers



Aug. 9, 1966 SALOMON 3,265,824

ELECTROMAGNETI C CIRCUIT BREAKERS Filed July 13, 1964 2 Sheets-Sheet 1 FIG. 2

FIG. I

INVENT OR ROGER SALOMON BY fl ATTORNEYS,

Aug. 9, 1966 R. SALOMON ELECTROMAGNETIC CIRCUIT BREAKERS 2 Sheets-Sheet 2 Filed July 13. 1964 INVENTOR ROGER SALOMON ATTORNEY Unitcd States Patent 42,98 9 Claims. (Cl. 200-87) The present invention relates to circuit breakers such as those used in voltage and current regulators of generators, or in make and break switches connecting a generator to a battery.

When electromagnetic circuit breakers are of the type comprising an electromagnet and a movable contact element the latter must offer a certain resistance to the pulling force of the electromagnet.

Said resistance can be applied in different ways as for instance by having a coil spring biasing the movable contact element or a spring leaf urging the armature in a direction opposite the action of the electromagnet. In this second instance a known regulator has the free end of the leaf spring cooperate with a cam mounted on the breaker armature, the rotation of the cam allowing the adjustment of the electromagnetic force exercised on the spring to a desired value. The voltage regulation results from the action of the mechanical resistance of the spring opposing the pulling force of the electromagnet.

In a two stage voltage regulator two major adjustments occur, namely the voltage adjustment within each stage and the adjustment of passage from one stage to the other. The term of stage passage as used herein is defined as the voltage of the regulator suflicient to move the armature from the first stage contact to the second stage contact. As far as the adjustment of passage from one stage to the other is concerned it is necessary to modify either the air gap or the spring flexibility while keeping the initial tension of the spring necessary for the voltage regulation.

When using a coil spring connected to the armature at one end and to the movable contact element at the other end the voltage adjustment can be performed in production by tightening the spring and the stage passage adjustment can be obtained by substituting a spring of different flexibility for the one originally mounted on the device.

When a leaf spring is used it is difficult to obtain the necessary adjustments because said spring has one embedded end and is therefore hardly interchangeable.

The primary object of the invention is to remedy this disadvantage and provide an additional adjustment means for passage between stages without need for use of an interchangeable leaf spring. H

The invention specifically concerns an electromagnetic circuit breaker of the type including an electromagnet, a movable armature carrying a contact element, and a leaf spring attached to the armature having a fixed end and the other end cooperating with a stop so as to elastically urge the movable armature and contact element in a direction opposite the action of the electromagnet, said circuit breaker further comprising means for varying the flexibility of the leaf spring either by altering its effective length or by modifying its effective section which permits in mass production, and more specifically in the instance of a two-stage regulator, a ready adjustment of the stage passage by varying the characteristic displacement force of the leaf spring.

The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention self, however, both as to its organization and its method of operation, together 3,265,824 Patented August 9, 1966 ice with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein like reference characters indicate like parts throughout the several figures and in which:

FIG. 1 is an end elevation of an electromagnetic circuit breaker according to the invention wherein the variation of flexibility of the leaf spring is obtained by modifying its effective length;

FIG. 2 is a side elevation, partly in section of the circuit breaker;

FIG. 3 is a plan view of another embodiment of the invention wherein a variation of flexibility of the leaf spring is obtained by changing its effective section;

FIG. 4 is a schematic, side elevational representation of a possible embodiment of the invention wherein only one cam is used divided in several segments located in different planes;

FIG. 5 is a schematic, plan view of the cam utilized in the embodiment of FIG. 4;

FIGS. 6 and 7 are schematic views similar to FIG. 4

of other possible realizations of the invention for changing the point of application of the leaf spring on its stop and the restraining force of said spring.

The circuit breaker shovm in FIGS. 1 and 2 comprises a frame 1 on which is secured a vertical iron core 2 which supports 'the excitation winding 3. A movable armature 4 is hingedly secured to frame 1 by a leaf spring 5 aflixedto both. The connection of armature 4 with frame 1 can be realized by means of a separate and distinct leaf spring 6 as shown in FIGS. 1 and 2, or by an extension of the leaf spring 5.

In a known manner, the armature 4 carries a contact 7 cooperating with a fixed contact 8 secured to frame 1.

In a preferred embodiment of the invention the voltage adjustment for opening the breaker is provided by having the free end of leaf spring 5 rest on the cam edge 9 of a cam 9 rotatably mounted on the front portion of frame 1. A toothed sector 9 enables said cam 9 to be rotated to lift the free end of the spring to various heights for accurate adjustment of the restraining force of the spring. According to the invention, in order to provide in mass production an adjustment of the stage passage in addition to the voltage regulation in a two-stage circuit breaker, it is necessary to vary the flexibility of 'leaf spring 5, that is the location of the point of spring contact on the stop means constituted by cam 9.

i A first method of varying the flexibility of the spring 5 is to modify its effective length. One possibility for accomplishing this is to make cam 9 interchangeable. For this purpose, the cam may be removably secured to frame 1 by a screw 10 permanently attached to said frame by welding or any other means and a nut 11. This permits change of the position of the cam contact with leaf spring 5 by choosing an appropriate cam.

It should'be noted that the profiles of the different usable cams may be identical, or different, to allow a greater sensitiveness of voltage regulation, but the spring engaging cam edges of these cams must be positioned differently lengthwise of the spring.

As an example, there has been shown in FIG. 2, three cams (two in broken lines) which could be used for varying the flexibility of leaf spring 5 by changing the effective length of said spring. It will be noted that, depending upon which one of the three cams 9, 12 and 13 is used, the point of contact of leaf spring 5 with the differently oriented cam edges 9 12 13 will be dis-. placed from A to B or C.

In the embodiment of FIGS. 4 and 5, instead of replacing one cam by another to obtain the desired adjustment only one cam 9 is used which is divided in several sectors a, b and each located in a different plane.

According to another method of realizing the invention 7 for adjusting the stage passage in a two-stage voltage regulator, it is possible to vary the flexibility of the leaf spring by changing its effective section as illustrated in FIG. 3. Leaf spring S is trapezoidal in shape, or 'rectangular if desired, but of decreasing thickness, or still better, characterized by a combination of a given profile and thickness, and instead of being permanently affixed to armature 1 is susceptible of assuming different positions relatively to cam 9. For this purpose, spring 5 is provided in the securing area with slots 14 which cooperate with guides such as clamping screws 15 fastened into threaded opening in armature 4. A number of pos sible positions of leaf spring 5 relative to cam 9 are obtained by loosening and retightening the screws.

Inthe embodiment of FIG. 6, an adjustable stop means 16 is substituted for cam 9 and is secured to armature 1 by means of adjusting screw 17. In this specific instance stop means 16 comprises a U-shaped strip bolted by means of screw 17 which passes through the two branches 16 and 16 in such a manner that the adjustment of said screw 17 will displace branch 16 in the direction xy.

thereby varying the location of the contact point of spring 5. Said spring 5 rests upon the head of a screw 18 secured into an extension 16 of branch 16 said screw 18 permitting variation of the restraining force on leaf spring 5 in the direction xy' for adjusting the cut-off voltage.

In the embodiment illustrated in FIG. 7, stop means 19, also secured to armature 1 by suitable means not shown, consists of a leaf having a bent portion 19 onto which the end of leaf spring 5 rests. Said leaf 19 and/ or portion 19 can be subjected to different deformations by any appropriate means in both directions xy and x'y.

In the embodiments of FIGS. 6 and 7, the deforma tion in the direction xy results in the displacement of the point of contact of leaf spring 5 which provides the adjustment between stages, and the deformation in the direction x'y' results in the variation of the restraining force for adjusting the voltage.

Although certain specific embodiments of the invention have been shown and described, it' is obvious that many modifications thereof are possible. The invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

What is claimed is:

1. An electromagnetic circuit breaker comprising an electromagnet supported on a fixed frame, a movable armature carrying a contact element, a leaf spring fixed at one end to said frame and secured to said armature, a stop engaging the other end of said spring so as to elastically urge the armature in a direction opposite the attraction of the electromagnet, and means provided on said stop for varying the point of engagement lengthwise of said spring to thereby vary the flexibility of the leaf spring.

2. An electromagnetic circuit breaker according to claim 1 wherein said means for varying the flexibility of the leaf spring comprises a removable cam whereby a plurality of cams having surfaces in different planes lengthwise of the spring may be interchangeably mounted on said stop.

3. An electromagnetic circuit breaker according to claim 1 wherein said means for varying the flexibility of the leaf spring comprises a single cam divided in several sections located in different planes lengthwise of the spring.

4. An electromagnetic circuit breaker according to claim 1 wherein said means for varying the flexibility of the leaf spring comprises an elastic element on which said leaf spring rests and having adjustable means for clamping to said stop to vary the point of engagement lengthwise of the leaf spring, and additional means on ceptible of deformation insat least two directions secured to said stop and engaging said spring, the deformation of said element in one direction away from the electromagnet permitting the adjustment of the restraining force of the spring, and the deformation in the other direction lengthwise of the spring permitting the variation of the location of the point of contact of the leaf spring.

6. An electromagnetic circuit breaker according to claim 1 wherein said leaf spring varies in cross section along its length and said means for varying the flexibility of the spring comprises means displacing said leaf spring lengthwise between points of securement of said one fixed end and the other end Which rests on said stop.

7. An electromagnetic circuit breaker according to 7 References Cited by the Examiner UNITED STATES PATENTS 1,769,279 7/1930 True 200166 2,453,106 11/ 1948 Yardeny et al 200166 2,896,048 7/1959 Wood 200104 2,911,497 11/ 1959 Prickett 200 2,995,812 8/1961 Bates 29--404 3,014,103 12/1961 Moran et al 20087 3,018,347 1/1962 BERNARD A. GILHEANY, Primary Examiner. J. J. BAKER, Assistant Examiner.

Deer et al. 20087 

1. AN ELECTROMAGNETIC CIRCUIT BREAKER COMPRISING AN ELECTROMAGNET SUPPORTED ON A FIXED FRAME, A MOVABLE ARMATURE CARRYING A CONTACT ELEMENT, A LEAF SPRING FIXED AT ONE END TO SAID FRAME AND SECURED TO SAID ARMATURE, A STOP ENGAGING THE OTHER END OF SAID SPRING SO AT TO ELASTICALLY URGE THE ARMATURE IN A DIRECTION OPPOSITE THE ATTRACTION OF THE ELECTROMAGNET, AND MEANS PROVIDE ON AND STOP FOR VARYING THE POINT OF ENGAGEMENT LENGTHWISE OF SAID SPRING THE POINT OF ENGAGEMENT LENGTHWISE SPRING. 